1. Field of the Invention
The present invention relates to a magenta ink for ink-jet recording.
2. Description of the Related Art
In an ink-jet recording method, a magenta ink is required in order to form a full-color image. Generally known examples of the magenta dye used in such a magenta ink include C. I. Acid Red 14, C. I. Direct Red 227 and the like. Here, C. I. Acid Red 14 is a monoazo xanthene-based dye that is capable of imparting relatively good ejection stability and color developing properties to an ink, and C. I. Direct Red 227 is a disazo-based dye that is capable of imparting relatively good ejection stability to an ink (U.S. Pat. No. 6,228,156).
In recent years, an ink for ink-jet recording is required to not only exhibit good ejection stability and color developing properties but also to have additional characteristics such as a high level of light fastness and resistance to active gas such as ozone. Therefore, the dyes such as C. I. Acid Red 14 and C. I. Acid Red 227 are also required to exhibit these characteristics.
However, the magenta dyes such as C. I. Acid Red 14 and C. I. Direct Red 227 described above do not have sufficient light fastness and ozone resistance. Therefore, in an ink-jet recorded image produced using an ink-jet recording magenta ink containing either of such dyes, the degree of deterioration of the image is not insignificant even under normal storage conditions.
As described above, among magenta dyes commonly employed in a magenta ink for ink-jet recording, magenta dyes such as C. I. Acid Red 14 have relatively good color developing properties, i.e., they provide vivid color and have a hue suitable for obtaining a wide range of colors by color mixing. However, these dyes tend to have a relatively low level of light fastness and ozone resistance.
Meanwhile, a magenta dye such as a 1-alkyl-3-alkyl or aryl-4-cyano-pyrazole-5-yl azo dye disclosed in U.K. patent No. 1,566,985 is known to have relatively good light fastness and active gas resistance. However, a heavy metal cyanide is used in the manufacture of the dye, thereby causing problems with waste treatment. In addition to this, such a magenta dye has a hue insufficient to obtain a wide range of colors by color mixing and also has insufficient vividness. Furthermore, such a magenta dye is likely to cause problems when it comes into contact with various members employed in an ink-jet recording apparatus. Therefore, a problem exists with ejection stability during long-term use in an ink-jet printer provided with an ink-jet recording magenta ink in which such a magenta dye, having relatively good light fastness and active gas resistance is employed.